The use of contact lenses to correct vision is common place in today's world. There are presently several traditional methods of high-volume, low-cost contact lens manufacture. These methods include, but are not limited, to cast molding, spin casting, lathing, using a technique known in the industry as “Lightstream Technology”, and any combinations thereof.
More recently, a new system and method for manufacturing contact lenses has been disclosed in which an infinite number of truly custom lenses can readily be produced in a cost effective manner. U.S. Pat. No. 8,317,505, which is incorporated herein by reference in its entirety, discloses a method for growing a Lens Precursor Form on a single male optical mandrel on a Voxel by Voxel basis by selectively projecting actinic radiation through the optic mandrel and into a vat or bath of a Reactive Mixture. The optical mandrel and Lens Precursor Form are then removed from the vat and inverted so that the convex surface of the optic mandrel is upright. Following a dwell period during which uncured residual liquid from the bath that remains on the Lens Precursor Form flows under gravity or otherwise over the Lens Precursor Form, the liquid is then cured by applying Fixing Radiation to form the final lens. As described therein, a truly custom lens can be produced for any given eye.
Incorporating various features into contact lenses that are incidental to or not at all relevant to vision correction has also been disclosed. For example, lenses have been known to incorporate fiducial marks that assist a vision care practitioner in assessing the fit of a lens on a patient, but do not relate to the corrective power of the lens. These known fiducial markings are separately placed or encapsulated within the lens, which typically requires an additional manufacturing step. In the case of encapsulation, the item is placed between separately cured layers of the lens, which negatively affects the structural integrity of the lens layers. Other methods of placing these types of markings on a lens include milling, scribing, stamping, ink jet printing, pad printing or the like, or incorporating features into the cast mold pieces. Another method is to subsequently add or remove material from the lens such as is disclosed in U.S. Pat. No. 8,636,357. The cost and complexity or these additional manufacturing steps increases the cost of the lens. Further, known methods of separately placing markings on the surface of a lens adversely affect the optical quality surface, often negatively affecting patient comfort as well.
Accordingly, it is desirable to provide an improved system and method for incorporating fiducial marks, or other cosmetic or functional indicia such as pictures, logos, identification marks or numbers (referred to collectively herein as “lens features”) into a contact lens, and lenses incorporating such lens features.